This invention relates to an imaging device, more particularly, to an imaging device employing a recording medium which carries thereon a plurality of photo and pressure sensitive microcapsules, each microcapsule containing therein a dye precursor and a photo-curable resin.
The imaging device of this type generally comprises exposure means for exposing the recording medium to an optical image information so as to form a latent image thereon corresponding to an image to be recorded, a pressure-developing means for pressing the recording medium carrying the latent image to develop a visible image thereon, and transporting means for transporting the recording medium from the exposure means to the pressure development means.
With the above imaging device, the latent image is formed on the recording medium by exposing the optical image thereon to selectively cure the photo-curable resins enveloped in the microcapsules existing on the area corresponding to the exposed optical image. The latent image thus formed on the recording medium is then transferred and developed on a separate developing medium on which a developer is coated. Transferring of the image is executed by superposing the recording medium and the developing medium one on the other and pressurizing the superposed mediums so that the unhardened microcapsules on the recording medium are ruptured by the applied pressure and the dye precursors enveloped therein are streamed out of the ruptured microcapsules. The streamed-out dye precursors are reacted to the developer coated on the developing medium so as to form the visible image thereon corresponding to the above latent image.
In order to make the arrangements in the device and maintenances therefor simple and easy, the continuous type of the above recording medium, one end of which is rolled on a feed roll while the other end on a take-up roll, has been employed. With this continuous type recording medium, it is fed from the feed roll to the take-up roll through the exposure and the pressure-developing means. When it passes the exposure means, the latent image is formed thereon, and when it passes the pressure-developing means, the latent image is transferred and developed on the cut-sheet type developing mediums which are successively supplied to be superposed on the corresponding areas of the continuous recording medium before it reaches the pressure-developing means.
With the imaging device employing the above continuous type recording medium, however, there exists one problem. That is, there is a possibility that the pressure-developing means is polluted by the components streamed out of the microcapsules when the recording medium is pressurized without the developing medium superposed thereon. This occurs, for instance, each time the imaging operation is started after the prior imaging operation is once terminated. That is, since the last exposed portion of the continuous recording medium must have at least been transported to the pressure-developing means from the exposure means before terminating the operation, there remains on-exposed portion of the continuous recording medium between the exposure means and the pressure-developing means. This non-exposed portion must pass the pressure-developing means when the beginning portion of the continuous recording medium on which the latent image is formed in the next imaging operation is transported to the pressure-developing means.
In order to dissolve the above problem, the pressure applied by pressure-developing means, for instance, by a pair of pressing rollers, must be released to freely pass the non-exposed portion of the continuous recording medium. It is, however, cost-consumptive and complicates the arrangements to design, for instance, one of the pressing rollers movable away from the other during the passing of the non-expose portion of the continuous recording medium while properly pressurising the exposed part of the continuous recording medium at substantially constant pressure value.